The purpose of this research is to investigate possible differences in HDL cholesterol, in HDL2 and HDL3, in apolipoprotein B, and in serum SGOT and GGT levels in relation to patterns of alcohol intake. We also plan to study the possible relationship of anginal pain and other cardiac symptoms to drinking patterns. Patients scheduled for aortocoronary bypass surgery in two Milwaukee, Wisconsin area hospitals will be the source of subjects for this study. 1500 patients will be studied over a three-year period. At the time of hospitalization for angiography, patients will be requested to complete a comprehensive questionnaire containing items on demographic background, family history of heart disease, past and present cardiac symptoms, types and amounts of medications taken, employment history, smoking history, non-job related physical activity, and a series of questions on alcoholic intake and pattern of drinking behavior. Fasting blood specimens for serum enzyme and lipid determination will be obtained, and the degree of coronary occlusion as indicated by angiography will be recorded. The major hypotheses to be tested focus on the possible mediating roles of serum lipids in relating drinking patterns to coronary occlusion in both men and women.